The US State Department has condemned a violent confrontation between Turkish President Recep Tayyip Erdogan’s bodyguards and protesters in Washington, DC.

"We are communicating our concern to the Turkish government in the strongest possible terms," State Department spokeswoman Heather Nauert said in a statement on Wednesday. “Violence is never an appropriate response to free speech.”

The crackdown erupted earlier in the day, when protesters gathered outside the Turkish ambassador’s residence, where Erdogan was staying after meeting with his American counterpart Donald Trump at the White House, according to presstv.ir.

The peaceful protests turned into violent clashes when a group of Erdogan’s supporters taunted the first group and attacked them.

The situation escalated after Erdogan’s guards and other Turkish security personnel interfered and violently beat the protesters.

DC Police said at least 11 people were injured and two arrests were made during the melee. Two US Secret Service agents were also assaulted in the brawl, an officer said.

Police Chief Peter Newsham said the incident was nothing but a “brutal attack” on peaceful protesters. His department was investigating the matter with the State department and the Secret Service.

DC Mayor Muriel E. Bowser decried the incident as a “pretty savage beating” and said police and all city officials were determined to resolve the situation.

Republican Senator John McCain also censured the “thuggish behavior.”

“This is the United States of America. We do not do this here. There is no excuse for this kind of thuggish behavior,” the Arizona lawmaker said.

Ankara responds

The Turkish embassy said the protesters were linked to the Kurdistan Workers Party (PKK) and the demonstration was “unpermitted” and “provocative.”

According to the embassy, the Turkish guards acted in self-defense against people “aggressively provoking Turkish-American citizens who had peacefully assembled to greet the president.”

Turkey's state-run Anadolu news agency blamed DC police and officials, saying it was “inadequate” response on their part that led to the violence.

The demonstrators talked to the media after the clashes and recalled how they were kicked by security personnel.

Footage of the fight shows outnumbered police officers engaging some of the Turkish guards as they brutally beat people.

Erdogan’s trip to the US came days after Ankara strongly criticized Washington over its decision to arm Kurdish militants.

The Syrian Democratic Forces (SDF) is led by the Kurdish People's Protection Units (YPG) which Ankara views as a terrorist organization over its alleged links to the outlawed Kurdistan Workers’ Party (PKK).

After meeting Trump, the Turkish head of state said "there is no place for the terrorist organizations in the future of our region."